First I would like to say that if I owned my house I would have a Spring pole like Sydneys. But My landlords are jurks so I had to improvise.
I made this for $25 from Lowes. I got everything there except the Bite surface.
Things you will need:
1.Eye Hook (Large enough for the chain to go through)

2.Chain (length depending on the size of tree being used)

3. (Qty 3) Locking Karabiners (One smaller than the other two. It has to fit into the chain link.)

4. Heavy duty spring

5. Rope (Buy more than you think you will need better to be safe than sorry)

6. Bite Surface. (Hide, Mini chew tire, Old cloths)

7. Duct tape or electrical tape.
Directions:
1. Screw the eye hook into the top of a horizontal branch.
- This provides an anchor for the chain so it doesn't move along the branches length.
- Common sense... pull on the branch a few times urself to simulate the dogs movements on the springpole. Make sure it can support his weight plus.
2. Place the chain thru the eye hook so that both ends dangle under the branch.
3. Place the small karabiner thru both end links. Then place the larger one through the small one. Make sure to test the width of the karabiner against the size of the holes in the links of the chain before you buy it.
4. Place the loop of the spring onto the large karabiner and lock it closed.
- Make sure to check the max load on the spring to ensure ur dogs safety. Also very important is to make sure that the karabiner is thick enough not to slip thru the gap on the ring of the spring end. If you look at the pic of the spring you can see what i mean.
5. Place the third karabiner on the other end of the spring and lock it closed.
6. Tie one end of the rope to the karabiner with several knots and then tape the knots so they do not release.
- Tape them the same way you would the grip of a baseball bat or hockey stick.

7. Check the height of ur dog to where the end of the rope should be and leave alittle extra for knots to attach the grip.
- Your dogs back legs should always be able to touch the ground to prevent injury.
8. Affix gripping item and tape off any knots created.
- I punctured two holes in a deflated soccer ball and threaded the rope thru both then tied and taped it off. Works well for me. Use whatever ur dog likes best.
Here is what it looks like mocked up befor on the tree.

Good luck and remember to triple check all construction. Your dog will thank you for it.
I will have pictures of it up tomorrow hopefully.
Let me know if you have any other questions.
Jay (Kanes DAD)